The present invention relates to new 3-mercapto-alkanols and their stereoisomers, to flavoring compositions and to food or beverage products flavored with at least one of these compounds, and to a method for the preparation of both diastereoisomers of 3-mercapto-2-methyl-butan-1-ol.
In the food and beverage industry flavors play a critical role in the appreciation of food and beverage products. Hereafter the term flavor shall also include aroma and/or taste and in the following context all these terms are used interchangeably.
Several mercapto-alkan-1-ol compounds have been identified as flavorants in food products. Thus, 3-mercapto-hexan-1-ol has been identified in the yellow passion fruit (Passiflora edulis f. flavicarpa) (K. -H. Engel, R. Tressel, J. Agric. Food Chem. 1991, 39, 2249), in Sauvignon blanc wine (T. Tominaga, A. Furrer, R. Henry, D. Dubourdieu, Flavour Fragrance J. 1998, 13, 159; P. Werkhoff, M. Gxc3xcntert, G. Krammer, H. Sommer, J. Kaulen, J. Agric. Food Chem. 1998, 46, 1076), and in red Bordeaux wine (P. Bouchilloux, P. Darriet, R. Henry, V. Lavigne-Cruxc3xa9ge, D. Dubourdieu, J. Agric. Food Chem. 1998, 46, 3095), and is usually described as having passion fruit and grapefruit character. 3-mercapto-3-methyl-butan-1-ol has been found in roasted coffee (W. Holscher, O. G. Vitzthum, H. Steinhart, J. Agric. Food Chem. 1992, 40, 655) and in Sauvignon blanc wine (T. Tominaga, A. Furrer, R. Henry, D. Dubourdieu, Flavour Fragrance J. 1998, 13, 159). The flavor description by Holscher et al. is sweet, soup-like.
3-mercapto-2-methyl-propan-1-ol has been identified in red Bordeaux wine (P. Bouchilloux, P. Darriet, R. Henry, V. Lavigne-Cruxc3xa9ge, D. Dubourdieu, J. Agric. Food Chem. 1998, 46, 3095) and has been described as broth, sweat-like.
The German Offenlegungsschrift 2316456 describes xcex3-mercapto-alcohols and their formate and acetate esters as important odorants and flavorants that are useful for the preparation and modification of a broad range of flavor compositions. These compounds have been described as faint green, onion-like, sulfury and sweaty with a broad range of taste thresholds.
New 3-mercapto-alkan-1-ols for use as flavor ingredients and/or as flavor enhancer are provided.
The invention is directed to new 3-mercapto-alkanol compounds. One of these compounds is 3-mercapto-2-methyl-butan-1-ol (formula 1) 
and stereoisomers of 3-mercapto-2-methyl-butan-1-ol. Another of these compounds is 3-mercapto-3-methyl-hexan-1-ol (formula 11) 
and stereoisomers of 3-mercapto-3-methyl-hexan-1-ol. In one embodiment, the compound is a stereoisomer of 3-mercapto-2-methyl-butan-1-ol having a relative unlike (u) configuration (formula III) 
or the enantiomer of ll. In an alternative embodiment the compound is a diastereomer of 3-mercapto-2-methyl-butan-1-ol having a relative like (I) configuration (formula IV) 
or the enantiomer of IV.
The above compounds may be used as flavorants in foods and/or beverages. The 3-mercapto-2-methyl-butan-1-ol and stereoisomer compounds provide cooked vegetable and meaty flavor/aroma notes to food products. The (S) isomer of 3-mercapto-3-methyl-hexan-1-ol enhances meaty notes, while the (R) isomer of 3-mercapto-3-methyl-hexan-1-ol enhances natural fruity character of exotic fruit flavors.
The invention is also directed to a flavor composition containing one or a combination of these compounds. In alternative embodiments, the flavor composition contains (rac)-3-mercapto-3-methyl-hexan-1-ol, (S)-3-mercapto-3-methyl-hexan-1-ol, or (R)-3-mercapto-3-methyl-hexan-1-ol. The compound in the flavor composition is at a concentration in the range of about 0.01 ppb to 50 ppm. The invention is also directed to a food or beverage product containing the above flavor compositions.
The invention is further directed to a method of flavoring a product, such as a food, beverage, oral hygiene product, pharmaceutical, or chewing gum, by adding one or a combination of the above compounds in an amount sufficient to flavor the product. The concentration of the compound may be in the range of about 0.01 ppb to 50 ppm.
The invention is still further directed to methods to synthesize 3-mercapto-2-methyl-butan-1-ol and stereoisomers, and 3-mercapto-3-methyl-hexan-1-ol and stereoisomers.